Input-output circuit and a testing apparatus

Abstract

An input-output circuit sending and / or receiving a signal to and / or from an electronic device includes a driver for supplying a signal to the electronic device, a comparator provided parallel to the driver for receiving a signal from the electronic device, a relaying circuit provided between the comparator the electronic device in series with the comparator and the electronic device, a first transmission line for coupling the comparator and the relaying circuit electrically and a first switch for selecting either of short or open-circuited state of the first transmission line and the electronic device, wherein the impedance of the relaying circuit is larger than the impedance of the first transmission line.

Description

[0001]The present application is a continuation application of PCT / JP02 / 07259, filed Jul. 17, 2002 which claims priority from a Japanese patent application No. 2001-216792 filed on Jul. 17, 2001, the contents of which are incorporated herein by reference.FIELD OF THE INVENTION[0002]The present invention relates to a testing apparatus for testing an electronic device and an input-output circuit for sending and / or receiving signals to and / or from the electronic device. More particularly, the present invention relates to a testing apparatus capable of testing the direct current and alternating current characteristics with high accuracy, and an input-output circuit capable of sending and / or receiving direct current signals and alternating current signals to and / or from the electronic device with high accuracy. In addition, the present application claims the benefit of, and priority to, Japanese patent application No. 2001-216792 filed on Jul. 17, 2001, the entire contents of which are i...

AI Technical Summary

Benefits of technology

The present invention provides a testing apparatus and an input-output circuit that can overcome the problems of conventional art. The input-output circuit includes a driver, a comparator, a relaying circuit, and a first transmission line with a switch for selecting either a short-circuited or open-circuited state of the line and the electronic device. The relaying circuit has larger impedance than the first transmission line and can be connected between the comparator and the electronic device. The impedance of the terminal circuit may be equal to the impedance of the first transmission line. The second switch can be short-circuited or open-circuited based on the driver or comparator. The testing apparatus includes a pattern generating unit, a waveform adjusting unit, and an input-output circuit for supplying a test pattern to the electronic device and receiving an output signal. The input-output circuit includes a driver, a comparator, a relaying circuit, and a first transmission line with a switch for selecting either a short-circuited or open-circuited state of the line and the electronic device. The technical effects of the present invention include improved signal quality, reduced signal loss, and improved testing accuracy.

Problems solved by technology

Thus, the size of the circuit such as the driver comparator is increased, and it is difficult to arrange the driver comparator to be close to the device under test.

Accordingly, although the driver comparator and the device under test are electrically coupled by using a long transmission line, it causes the parasitic capacitance component of the transmission line to be increased.

The output signals of the electronic device are given to the comparator via the transmission line, but the distortion might occur in the output signals because of the capacitance component of the transmission line.

For example, there is the distortion such as the delay of the rising of the waveform.

If the delay of the rising of the waveform occurs, it is difficult to perform the test with high accuracy, and difficult to test the device by using the test pattern of high frequency.

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